666 



Accessory Food Factors. 



[Oct., 



ACCESSORY FOOD TFACTORS, 

 OR YITAMINES. 



Tee reference in the June issue of this Journal to Sir Daniel 

 Hall's Third Chad wick Lecture, in which a short account of 

 " vitaruines," or accessory food factors, was given, has led to 

 a request for the publication of further information on the 

 subject. A full account of the present state of knowledge con- 

 cerning accessory food factors, by the National Health Insur- 

 ance Medical Research Committee, was published in 1919, and 

 the account here given is a summary of that report.* 



Accessory food factors — so called because the foods in which 

 they are present contain them only in minute amounts — play 

 a prominent part in nutrition, since, if these minute amounts 

 are removed from natural foods, such foods fail to maintain 

 healthy nutrition, and grave symptoms of actual disease may 

 supervene. Among the diseases which have definitely been 

 shown to be produced by the absence of these factors are 

 scurvy, rickets and beri-beri. Research suggests that the 

 nature of vitamines is quite distinct from that of proteins or of 

 foods which supply energy, but at present we have no know- 

 ledge concerning their actual chemical nature. It is thought 

 that they may either (a) be structural components of living 

 tissues of which a supply is essential, though quantitively 

 unimportant, or (b) that they may act rather as catalysts in 

 certain normal processes of metabolism. There is evidence to 

 suggest that these accessory food factors are formed only in the 

 tissues of plants, whence they pass into the tissues of 

 herbivorous animals and thus become available for carnivora. 



Vitamines are always present in natural foodstuffs as 

 instinctively consumed by men and animals; broadly speaking, 

 it is safe to say that the individual always finds a sufficient 

 supply of vitamines in his food, so long as that food is reason- 

 ably varied and has received no artificial or accidental separa- 

 tion into parts, and so long as no destructive influence has been 

 applied to it. 



Clear evidence has been obtained of the existence of three 

 accessory food factors: — 



(1) Fat Soluble A Factor. — This term was given to this factor 

 by American investigators, as it is soluble in fats and accom- 

 panies them in the process of isolation from certain food- 



* Special Report Series No. 38, H.M. Stationery Office, 1919, 4s. net. 



